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Montana waters bond mountaintops to riverbeds, connect cities upstream with communities downstream, and provide the link between generations.

Join us in keeping our waters clean, clear, and connected.

What you can do

Explore the different parts of your watershed by hovering over the labels in the graphic below!

Agriculture Agriculture Groundwater Groundwater Flathead national forest Flathead national forest urban area urban area Flathead Wild & Scenic River Flathead Wild & Scenic River Wetlands Wetlands GLACIER NATIONAL Triple Divide Pass GLACIER NATIONAL Triple Divide Pass dams and reservoirs dams and reservoirs Whitefish Lake Whitefish Lake Residential area & subdivision Residential area & subdivision


The Headwaters of North America: Precipitation that hits Triple Divide Pass drains into the Pacific, Arctic, and Atlantic oceans. As rainwater and melting snow run downhill, they can carry soil, pollutants, and other materials from the land into our rivers and lakes.


Healthy forests increase water supply reliability, reduce flooding risks, improve water quality, reduce impacts from catastrophic wildfires, enhance habitat, provide accessible recreation, and improve response to climate change and extreme weather events.

Home to several threatened and endangered species, the Flathead Watershed has the largest grizzly bear population in the interior of North America, as well as populations of black bears, deer, elk, bighorn sheep, mountain goats, lynx, bobcats, gray wolves, wolverines, and a host of small mammals. Wild turkeys, grouse, bald eagles, peregrine falcons, hawks, owls, jays, chickadees, nuthatches, and numerous other birds call northwest Montana home. Clean water is vital to their survival, and their existence is vital to the survival of the Flathead ecosystem.


Healthy lakes and rivers provide a safe and enjoyable place for residents to recreate and ensure the continuing success of Montana’s tourism industry, upon which a large portion of our economy relies.


The dams and reservoirs of the Flathead Watershed provide drinking water, water storage, flood control, and electrical power to the residents of northwest Montana. Among these are the Hungry Horse Dam & Reservoir, Bigfork Dam, and the Seli'š Ksanka Qlispe' Dam, operated by the Confederated Salish & Kootenai Tribes (CSKT). The CSKT also operate an elaborate system of reservoirs, natural channels, and human-made irrigation canals to store and distribute water.


Farmers’ and ranchers’ livelihoods depend on clean water for irrigation, crops, and livestock.


Healthy streams and wetlands provide flood protection for communities, benefit fish and wildlife, filter pollution, and assist in groundwater recharge.

One-third of threatened and endangered bird species in the country live only in wetlands.

The stretch of the Flathead River between Kalispell and Flathead Lake has one of the highest populations of osprey nests in Montana, and the watershed as a whole serves as an important bird migration corridor.


Residents outside of centralized city sewer and drinking water systems likely consume water through wells and treat their wastewater with septic systems.

Water from inside our homes goes to a wastewater treatment facility or a septic system for purification. But water from roofs, driveways, streets, lawns, and outdoor spigots typically goes untreated directly into storm drains—straight to our waterways—potentially picking up contaminants, pollutants, and excess nutrients along the way.

The U.S. Environmental Protection Agency estimates that pollutants carried by rainwater runoff account for 70% of all water pollution. Rain gardens collect rainwater runoff, allowing the water to be filtered by vegetation and percolate into the soil recharging groundwater aquifers. These processes filter out pollutants.


Stormwater runoff is precipitation that falls onto impervious surfaces, such as roadways, driveways, parking lots, and rooftops, where it can accumulate pollutants, such as sediment, fertilizers, chemicals, oils, pet waste, and trash. Instead of being absorbed into the ground for natural filtration and treatment, stormwater moves over these surfaces and makes its way into our drainage system and waterways, typically untreated.

The wastewater from homes located within a water and sewer district is treated at a centralized wastewater treatment plant. Here, the water is filtered, treated, and sanitized before being discharged into surface water.


Native bull trout and westslope cutthroat trout spawn in the clear, icy tributaries of Flathead Lake.

The Flathead Watershed is also home to more than 300 species of aquatic insects, including 105 different stonefly species—a quarter of all stonefly species in North America.


Water is constantly being exchanged between the land surface and the subsurface. Surface water seeps into the ground and recharges the underlying aquifer, and groundwater discharges to the surface and supplies the streams and rivers.

Wells & drinking water – Your drinking water might come from a public water supply or from a private well. Public water supplies can source water from surface waters or deep wells. For example, the city of Whitefish utilizes surface water from Haskill Basin and Whitefish Lake, while the city of Kalispell sources water from numerous deep wells

Septic systems – Septic systems are underground wastewater treatment structures that use a combination of nature and technology to treat wastewater from bathrooms, kitchen drains, and laundry facilities. The septic tank digests organic matter, separates solids, and slowly releases the remaining liquid into the soil to be treated by microbes and bacteria.

What's New

    Living in the Flathead Guide

    Living in the Flathead Guide

    Learn more about what it means to be a responsible resident of the Flathead Watershed, whether you’re a new resident, a visitor, or a seasoned landowner!

    Flathead Basin Septic Risk Model

    Flathead Basin Septic Risk Model

    Help keep our waters clean and take a look at the Septic Risk Model.

    Pop-Up Displays & Signs

    Pop-Up Displays & Signs

    Need an eye-catching display for an event? Check out and download our newest pop-up designs!

    Communications Guide

    Communications Guide

    Check out our new communications guide for advertising strategies to keep our waters clean.

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